According to a configuration visible in FIGS. 1 and 2, an aircraft 10 comprises several engine assemblies 12 which are positioned under the airfoil 14 of the aircraft 10.
An engine assembly 12 comprises an engine 16, a nacelle (not represented in FIG. 2) positioned around the engine 16 and a pylon 18 which ensures the link between the engine 16 and the rest of the aircraft 10, in particular the airfoil 14.
The pylon 18 comprises a primary structure 20 which is linked to the engine 16 by a front engine mounting 22, a rear engine mounting 24 and a pair of torque arms 26 which ensure the absorption of the thrust loads.
According to an embodiment visible in FIG. 3, the front engine mounting 22 comprises a plate 28, secured to the pylon 18, which has two yoke joints 30 arranged on either side of the pylon 18, and two links 32 which each link one of the yoke joints 30 of the plate 28 to a yoke joint 34 secured to a casing of the engine 16. Thus, each link 32 is linked to one of the yoke joints 30 of the plate 28 by a first articulation axis 36 and to one of the yoke joints 34 of the engine 16 by a second articulation axis 38.
According to an embodiment visible in FIG. 4 and described in detail in the document FR3014971, an assembly between the yoke joint 34 secured to the engine 16 and the link 32 comprises an articulation axis 38 mounted in a first plain bearing 40 inserted into a first branch 34.1 of the yoke joint 34 and into a second plain bearing 42 inserted into a second branch 34.2 of the yoke joint 34, the articulation axis 38 supporting, between the first and second branches 34.1 and 34.2, a ball joint 44 configured to link the link 32 and the articulation axis 38.
The first plain bearing 40 comprises, at a first end, an outer flange 40.1 configured to bear against an internal face 34.1I of the first branch 34.1 and, at a second end, a shoulder 40.2 configured to block the translation of the articulation axis 38 in a first direction. The second plain bearing 42 comprises, at a first end, an outer flange 42.1 configured to bear against an internal face 34.2I of the second branch 34.2.
The articulation axis 38 is a cylinder which has an axis A38, a first end face 38.1, substantially at right angles to the axis A38, configured to bear against the shoulder 40.2 of the first plain bearing 40 and a second end face 38.2 substantially at right angles to the axis A38.
The assembly also comprises a blocking device 46 configured to block the translation of the articulation axis 38 in a second direction which, associated with the shoulder 40.2, makes it possible to block the translation of the articulation axis 38.
The blocking device 46 comprises:
an extension 48 of the second plain bearing 42 which has a tapped internal bore 48.1 and notches 48.2,
a blocking screw 50 that is screwed into the extension 48 which has a front face 50.1 bearing against the second end face 38.2 of the articulation axis 38 and a rear part 50.2 of hexagonal section making it possible to screw the screw 50,
a lock washer 52 comprising an opening 52.1 which is fitted over the hexagonal rear part 50.2 of the screw 50 and two tongues 52.2, diametrically opposite, which are housed in notches 48.2 of the extension 48 to rotationally immobilize the screw 50 relative to the extension 48,
an outer elastic stop ring 54 which is housed partially in an annular groove formed in the rear part 50.2 of the screw 50 making it possible to immobilize the lock washer 52 in the notches 48.2 of the extension 48, and
a pin 56 which passes through the extension 48 and the rear part 50.2 of the screw 50 to rotationally immobilize the screw 50 relative to the extension 48.
This embodiment makes it possible to obtain a two-fold rotational blocking of the screw 50 relative to the extension 48. However, the blocking device 46 thus obtained generates an addendum D, relative to the outer face of the branch of the yoke joint, that is significant given the stacking of the lock washer 52, of the outer elastic stop ring 54 and of the pin 56.
The present invention aims to remedy the drawbacks of the prior art.